<?php
define("TOKEN","jDeswu1EL4FJLGA3fcUbWh9FzHAgqpqWzsuVVVMvZY8"); //后台填写的token
	$wechatObj = new wechatAPI();
	$wechatObj->isValid();
	class wechatAPI
	{
	public function isValid()//验证微信接口，如果确认是微信就返回它传来的echostr参数
	{
	 $echoStr = $_GET["echostr"];
	 if ($this->checkSignature()) {
	 echo $echoStr;
	 exit;
	 }
	}
	private function checkSignature() //官方的验证函数
	{
	 $signature = $_GET["signature"];
	 $timestamp = $_GET["timestamp"];
	 $nonce = $_GET["nonce"];
	 $token = TOKEN;
	 $tmpArr = array($token, $timestamp, $nonce);
	 sort($tmpArr, SORT_STRING);
	 $tmpStr = implode( $tmpArr );
	 $tmpStr = sha1( $tmpStr );
	 if( $tmpStr == $signature ){
	 return true;
	 }else{
	 return false;
	 }
	}
	};

?>